The unified theory, macroevolution, and historical ecology

Abstract

The Darwinian revolution was based on the proposition that biological diversity is evolved diversity, and that evolution is a combination of genealogical (phylogenetic), developmental (ontogenetic), and environmental (selective) effects, but current theory concerns only the latter. The unified theory of evolution attempts to restore the macroevolutionary components of phylogeny and ontogeny to evolutionary explanation, along with selection. The unified theory asks new kinds of questions in evolutionary ecology. Phylogenetic constraints may limit the ways in which and the extent to which species adapt to different and changing environments, so it is possible that closely related species may have the same ecological or behavioural traits despite living in different environments. Two or more closely related species may live in similar habitats and yet exhibit divergent ecological or behavioural characteristics. Historical ecology uses phylogenetic trees to produce direct estimates of the origin and persistence of various aspects of ecological diversity and associations. It invokes two evolutionary processes, speciation and adaptation, to explain the evolution of diversity within clades, and invokes complementary processes of co-speciation and co-adaptation to explain the evolution of diversity in ecological associations.